Why We Think Ignorance Is Bliss, Even When It Hurts Our Health

Medical tests are rarely a pleasant experience, especially if you're worried that something could be seriously wrong. That's true even though we know that regular screenings and tests often help doctors catch issues early.

But of course, humans don't always behave rationally. Sometimes people will go to great lengths to avoid hearing bad news. Social scientists call this sort of behavior information aversion, or the ostrich effect (based on the old myth that ostriches bury their heads in the sand when they're scared). And it can have important implications for our health, researchers say.

In order to gauge how information aversion affects health care, one group of researchers decided to look at how college students react to being tested for a sexually transmitted disease.

That's a subject a lot of students worry about, according to Josh Tasoff, an economist at Claremont Graduate University who led the study along with Ananda Ganguly, an associate professor of accounting at Claremont McKenna College.

The students were told they could get tested for the herpes simplex virus. It's a common disease that spreads via contact. And it has two forms: HSV1 and HSV2.

The type 1 herpes virus produces cold sores. It's unpleasant, but not as unpleasant as type 2, which targets the genitals. Ganguly says the college students were given information — graphic information — that made it clear which kind of HSV was worse.

"There were pictures of male and female genitalia with HSV2, guaranteed to kind of make them really not want to have the disease," Ganguly says.

Once the students understood what herpes does, they were told a blood test could find out if they had either form of the virus.

Now, in previous studies on information aversion it wasn't always clear why people declined information. So Tasoff and Ganguly designed the experiment to eliminate every extraneous reason someone might decline to get information.

First, they wanted to make sure that students weren't declining the test because they didn't want to have their blood drawn. Ganguly came up with a way to fix that: All of the students would have to get their blood drawn. If a student chose not to get tested, "we would draw 10 cc of their blood and in front of them have them pour it down the sink," Ganguly says.

The researchers also assured the students that if they elected to get the blood tested for HSV1 and HSV2, they would receive the results confidentially.

And to make triply sure that volunteers who said they didn't want the test were declining it to avoid the information, the researchers added one final catch. Those who didn't want to know if they had a sexually transmitted disease had to pay $10 to not have their blood tested.

So what did the students choose? Quite a few declined a test.

And while only 5 percent avoided the HSV1 test, three times as many avoided testing for the nastier form of herpes.

For those who didn't want to know, the most common explanation was that they felt the results might cause them unnecessary stress or anxiety.

The researchers say that this study — and the growing body of evidence on information avoidance — has important implications.

Many health screening messages urge people to get tested by reminding them how awful diseases can be. But these scare tactics might be a mistake, Ganguly says.

"Scaring people more about the implications may scare them away from getting tested," he says.

That lines up with previous research. In a 2009 study that looked at adolescents in a high school and at a juvenile detention center, scare tactics about sexually transmitted diseases proved to be unnecessary for teenagers who were receptive to health messages. And they were ineffective for teenagers who were indifferent to such messages.

There's a second approach to consider, Tasoff says. The ostrich effect is produced by anxiety. One way to keep anxieties at bay is to draw as little attention to tests as possible, to make them routine.

Of course, these ideas need more testing. Keeping people in the dark about their health doesn't square with our notions of patient choice and autonomy. And if you don't tell people how bad a disease can be, that can affect the incentive to get tested at all.

But one thing seems clear. If we want people to pay attention to their health, it doesn't make sense to stick our heads in the sand about the ostrich effect.

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RENEE MONTAGNE, HOST:

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LINDA WERTHEIMER, HOST:

And I'm Linda Wertheimer. Today, in Your Health - why a life of purpose may be a longer life.

MONTAGNE: But first when a doctor tells a patient to undergo a test for a disease, the doctor may assume that the patient would want to know whether they have the disease. That's not always the case though. Often people prefer not to know, fearing bad news. Here's NPR's social science correspondent Shankar Vedantam but on some.

SHANKAR VEDANTAM, BYLINE: There's an old theory in economics about information, it makes common sense too. If I have some information about your finances or your health you should be willing to hear it. Maybe my information is useful, in which case you can act on it, maybe it's useless, in which case you can ignore it. If were a rational person says Josh Tasoff, an economist at Claremont Graduate University, here's one thing you should never do.

JOSH TASOFF: A person should never avoid information because information can never hurt a decision.

VEDANTAM: But of course people don't always behave rationally. We like information when the news is good and there other times we go, I'd rather not know. There's lots of new research that documents this behavior. Social scientists call it, information aversion. Tasoff and another researcher, Ananda Ganguly at Claremont McKenna College, recently decided to find out how information aversion, commonly called the ostrich effect, works in health. It's not rational to avoid accurate health information but what if the information is unpleasant. Here's the experiment they set up. They recruited a bunch of college students, they picked a subject.

TASOFF: Sexual transmitted diseases.

VEDANTAM: Tasoff says it's something lots of college students worry about. The students who volunteered were told they could get tested for the herpes simplex virus or HSV. It's a common disease that spreads via sex. It has two forms, one is unpleasant and the other is even worse. Ganguly says the college students were given information, graphic information that made it clear how bad herpes could be.

ANANDA GANGULY: There were pictures guaranteed to kind of make them really not want to have the disease.

VEDANTAM: Then once the students understood what herpes does, they were told a blood test could tell them if they had either form of the disease. Now in previous studies into information aversion it wasn't always clear why people declined information. So, Tasoff and Ganguly set out to eliminate the confusion by setting up the experiment in a certain way. First they wanted to make sure that students weren't declining the information because they didn't want to have their blood drawn. So, Ganguly came up with a way to fix that.

GANGULY: We were going to draw their blood anyway and discard the blood. If you can believe it we would draw 10 cc of their blood in front of them, have them pour it down the sink.

VEDANTAM: If the student elected to get the blood tested for herpes they would receive their results confidentially. So, being embarrassed was eliminated as a reason to decline the information. In fact Tasoff said the experiment was designed to eliminate every extraneous reason someone might decline to get information.

TASOFF: The idea is that all the costs associated with being tested are completely controlled for.

VEDANTAM: Finally, Tasoff and Ganguly added a step to the experiment to find out not just whether students wanted to avoid the information about herpes but how strongly they felt about not knowing. If students wanted to decline the test Ganguly told them they had to pay $10 and he asked them to think about it carefully.

GANGULY: You kind of have the sense that your blood is actually going to be wasted if you want to pay the money. So, you'd rather pay money, waste that blood than know what your test results were.

VEDANTAM: Did students declined to find out if they had disease? Yeah, quite a few. And Tasoff said there was a big difference in the number of students who avoided the test for the more unpleasant form of herpes. In fact three times as many students paid money not to find out they had genital herpes compared to herpes that causes cold sores.

TASOFF: For those who didn't want to know 85.7 percent, the most common explanation was because, quote, "it will cause me unnecessary stress or anxiety if I test positive."

VEDANTAM: Tasoff and Ganguly say their study and the growing body of evidence on information aversion, has a couple of important implications.

GANGULY: When we tell people, well you should get tested for disease X OR disease x, we tell them how bad it can be if they have those diseases it's something that we should look at as to whether we should scare people because scaring people more about the implications may scare them away from getting tested.

VEDANTAM: There's another take-home message Tasoff says.

TASOFF: Possibly, you know, an intervention that might address this is the routinization of tests. So, basically not draw their attention to it.

VEDANTAM: Both these ideas need more testing, but one thing seems clear, if you want people to pay attention to their health it doesn't make sense to stick our heads in the sand about the ostrich effect. Shankar Vedantam, NPR News. Transcript provided by NPR, Copyright NPR.